Sulphur phenoplasts and the obtaining thereof



United States Patent 3,408,328 SULPHUR PHENOPLASTS AND THE OBTAININGTHEREOF Yves Labat, Gelos, France, assignor to Societe Nationale desPetroles dAquitaine, Paris, France No Drawing. Filed Jan. 18, 1965, Ser.No. 426,429 Claims priority, appligcgtiogn grance, Jan. 21, 1964,

Claims. (Cl. 260-48) ABSTRACT OF THE DISCLOSURE The present inventionrelates to a process for the preparation of condensation products ofphenols with dithiol polythioethers. It also covers the new products asthus obtained and particularly new phenoplasts containing sulphur.

The preparation of condensation products of phenols, formaldehyde andhydrogen sulphite has long been known; more particularly, it is known toprepare resins with a base of sulphur, phenol and formaldehyde. However,the known products are not very well defined and their use as plasticmaterials has not met with any great success, the properties of 'thesematerials not being very interesting.

On the contrary, the present invention makes it possible to obtainmaterials which are much better defined and the properties of which areof interest for a certain number of uses. The new condensation productsdo in fact make it possible to prepare heat-hardenable materials havingproperties comparable to those of phenol-formaldehyde resins. Theinvention renders possible the preparation of readily melting resinswhich are partially soluble in the usual organic solvents and inalkaline solutions. It is possible to make the sulphur content in theseproducts to vary from about to 40%.

The new process according to the invention consists in causing a dithiolpolythioether to react with one or more phenols in such a way as tocondense these two reagents with release of hydrogen sulphide.

In practice, according to one particular embodiment of the invention,the dithiol polythioethers employed are of the HS(CH S),,H type, thenumber n of groups being generally between 2 and 7. These dithiolpolythioethers are preferably liquid oligomers which are more or lessviscous at normal temperature.

One particularly convenient form of the invention consists in usingliquid oligomers in which n has a value from 3 to 4 and of which themolecular weight is in the region of 190.

The condensation according to the invention of the phenols with theaforementioned liquid oligomers is carried out at temperatures whichvary from 45 to 180 C., in the presence of a catalyst of which thecontent is usually of the order of 0.1 to 10% by weight of the reactionmixture.

The condensation is effected with anhydrous reagents taken in the formof a liquefied mixture.

As catalyst, it is possible to employ the bases, preferably the loworganic bases and particularly the secondary aliphatic amines.

As in the manufacture of phenol-formaldehyde condensation products,different phenols can be employed but above all those of which the orthoand/ or para positions are free, i.e., are not substituted. Thus,phenols such as hydroxybenzene, metacresol, paracresol, alkylatedphenols, for example, those of which the alkyl contains 2 to 4 carbonatoms, resorcinol, etc., are suitable for carrying out the presentinvention.

In practice, it is possible to condense variable quantities of dithiolpolythioether on phenol; these quantities may be very small,particularly 0.1 mol per mol of phenol, or they may even reach 1.5 molsand more of oligomer to 1 mol of phenol.

Nevertheless, one particular feature of the invention consists inoperating with a slight excess of phenol or with a quantity of oligomerat most equal stoichiometrically to that of the phenol, taking intoaccount all the reactive positions of the phenol, that is to say, theunsubstituted ortho, para and/or meta positions. This method ofprocedure avoids having a too large quantity of phenol which has notreacted when the reaction is completed; on the other hand, the danger ofobtaining products containing chains of homopolymerised oligomer isavoided, and also that of the formation of a threedimensional lattice.The use of a slight excess of phenol thus avoids the conditions capableof leading to products which cannot be used as moulding powders.

In the embodiment of the invention which uses a slight excess of phenol,the preferred proportions are 1 to 2 mols of dithiol polythioetheroligomer to 2. mols of phenol.

On the other hand, the inventor has found that it is advantageous tostop the condensation reaction when to of the phenol has been condensed.If the reaction is continued beyond this limit, a thermo-setting resinis obtained which solidifies in the reactor; the final product no longercontains oligomer, even if its initial proportion is equal to or largerthan that of the phenol.

The period of the reaction is regulated as a function of the quantity ofhydrogen sul hide which is liberated; the liberation of H 8 stops whenthe reaction of the terminal -SH groups of the oligomer with thehydrogen of the phenolic nucleus is complete.

The invention also comprises the hardening of the sulphurisedphenoplasts obtained by the process as described above. Thistransformation of the resin may be carried out by means similar to thosewhich are used in the hardening of the known phenol-formaldehyde resins;in particular, one method of effecting the hardening consists in causingthe new sulphurised phenoplasts to react with substances whichgenerateactive methylene groups, such as for example polymethylenepolyamines and more especially hexamethylene tetramine.

The new products according to the invention, which are obtained by thecondensation of a dithiol polythioether HS(CH S),,H with a phenol,correspond to the formula:

which represents one of the units of the condensation product, thisbeing repeated x times in the molecule of the resin which is obtained.These compounds no longer contain an uncombined SH function, eachmolecule being terminated by two monosubstituted phenolic rings, exceptWhere x is l, in which case it is clear that the sulphurated chainterminates on both ends upon the phenolic moiety. The number x mayassume high values, but it is generally between 1 and 6, depending onthe degree of condensation. The number (n-l) of CH S groups in the saidunit is from 1 to 6 when starting with oligomers 3 of which n is 2 to 7and when the condensation occurs on a single hydrogen of the phenolwithout homopolymerisation of the oligomer. When other positions of the4 A total of 3.5 mols of H 8 has been liberated and the phenolconversion rate is 85%.

The resin obtained is light yellow and can easily be phenol occurparticularly the para and/ or meta positions, ground.

EXAMPLES 4 T 7 Total HzS total Phenol Resin S, Catalyst Phenol oligomerin 6 hours convetrsion percent re e No. of the example:

4 Diethylamiue--- 2 1. 2. 5 80 31 7 Dibutylamine 2 2 3. 5 38 and in thecase of the homopolymerisation of the dithiol polythioether-which occursparticularly when this latter is in excess with respect to the phenolthenumber of -CH S groups per unit may be much higher, for example 7 to 32.

Depending on the nature of the initial phenol or phenols and the dithiolpolythioether which is used, the new condensation products are obtainedin the form of a more or less solid wax or in the form of hard resinousmasses, the majority of which can easily be ground.

In the stage as mentioned above, that is to say, with relatively lowvalues for x, the resins which are obtained can be readily melted andare partially soluble in the normal organic solvents. Their sulphurcontent may be from to by weight, depending on the degree ofcondensation and the proportion of dithiol polythioether used in thepreparation of the condensation product.

The present invention also includes the hardened resins of which thetotal composition is that of the condensation products as describedabove, but in which all or part of the free ortho and/or para positionsof the phenolic rings which are present are substituted by othergroupings, particularly methylene groups.

The new condensation products according to the invention can be employedfor the manufacture of moulded articles, varnishes, etc., and loadingagents or other adjuvants can be incorporated thereinto in the usualway.

In order to illustrate the invnetion, a number of nonlimiting examplesare given below.

EXAMPLE 1 2 mols of phenol, 188 g., and 1 mol of oligomer, 190 g.,liquid at C. are mixed in a reactor which is equipped with a refluxcondenser and a pipe for the passage of a current of nitrogen. 3% ofdiethylamine related to the phenol, are then added, and the mixture isslowly brought to about 160 C. At the end of 3 hours, 1.7 to 1.8 mols ofH 5 are liberated. The rate of conversion of the phenol is 62%.

The uncombined phenol is then eliminated by vacuum distillation.

The resin obtained is light yellow and contains 28% of sulphur. It maybe crosslinked with hexamethylene tetramine.

EXAMPLE 2 The example is carried out under the same conditions, but withtwice the quantity of catalyst, i.e., 6% related to the phenol. 1.80 to1.90 mols of H 8 are liberated in 4 hours, and the conversion rate ofthe phenol is EXAMPLE 3 Example 1 is repeated with 2 mols of phenol and1 mol of oligomer in the presence of 6% of diethylamine with respect tothe phenol. The'reaction takes place at temperatures from 45 to 160 C.for 2 /2 hours. 1.6 molecules of H 8 are then liberated and the phenolconversion rate is 62%.

The temperature is then lowered to to C. and a fresh molecule ofoligomer is added. When the oligomerresin mixture is achieved, thetemperature is progressively raised to C. to C.

The reaction is stopped after a total period of 6 /2 hours.

The above examples are carried out in accordance with the working methoddescribed in Example 3.

EXAMPLE 8 In Example 5, the 2 molecules of phenol (hydroxybenzene) arereplaced by 2 molecules of metracresol and the other working conditionsare maintained. The reaction proceeds in identical manner. 3.5 mols of H8 are liberated and the phenol conversion rate is 87%. A clear resincontaining 37% of sulphur is obtained.

EXAMPLE 9 The resin obtained in Examples 2 to 8 is finely crushed andmixed with 10% of hexamethylene tetramine; the mixture is moulded at C.at a pressure of 250 kg./cm.

The moulded articles are infusible, light yellow in colour andodourless. They are not attacked either by the normal organic solventsor by acids. As regards the bases, only 10% caustic soda is absorbed bythese articles at the rate of 1.5% in 10 days.

I claim:

1. Process for the preparation of novel phenoplasts containing sulphur,characterized thereby that a phenol is heated with a dithiopolyetherwhereby hydrogen sulfide is liberated, and wherein (l) at least one ofthe positions on the phenol nucleus ortho or para to the hydroxy groupis unsubstituted,

(2) the dithiol polythioether has the formula HS (CH S) H where n has avalue from 2 to 7,

(3) the reaction is carried out in the anhydrous liquid state,

(4) the reaction is carried out in the presence of from 0.1%10% byweight of an aliphatic amine catalyst,

(5) the reaction is carried out at a temperature of between 45" to C.

2. Process according to claim 1 wherein n has a value between 3 and 4.

3. Process according to claim 1 wherein the phenol is a member of thegroup hydroxybenzene, metacresol, paracresol, ethylphenol, propylphenol,butylphenol and resorcinol.

4. Process according to claim 1 wherein the proportion of dithiolpolythioether to the phenol is between 0.1 to 0.5 mol per mol.

5. Process for the hardening of the condensation product formed inaccordance with claim 1 which comprises heating said product inadmixture with a substance which generates alkylene groups.

6. Process according to claim 5 wherein the alkylene generatingsubstance is hexamethylene tetramine.

7. A phenoplast having the general formula R n-lCIIT" 5 6 wherein thesulphurated side chain is bonded to the References Cited ortho or paraposition of the phenolic nucleus, UNITED STATES PATENTS 11382 to 32,2,035,098 3/1936 Seaman 26048 x 5 2,771,431 11/1956 De Groote et a1 25233s R is hydrogen or lower alkyl, and q is 1 or FOREIGN PATENTS 8.Product according to claim 7 wherein n is between 1330319 5/1963 France7 and 32. OTHER REFERENCES 9. An infusible phenoplast insoluble inorganic solvents, formed by heating a phenoplast of claim 7 in apolyalkylene amine.

10. A process of claim 1, characterized thereby that the condensation iseffected in several stages, a new por- WILLIAM SHORT P'lmary Examme"tion of dithiol polythioether being added to the phenol 15 H. SCHAIN,Assistant Examiner. in each of the stages.

10 Gould Phenolic Resins, 1959, pp. 27-28, 36, and

